题目内容
脱式计算(能简便的要简便) 327-59+33 |
(8×0.8)×125 | 15×[(48+24)÷18] | |||||||||||
24×(
|
|
分析:(1)运用加法交换律和结合律,先把327和33结合凑成整数,然后把59看作60-1,进行简算;
(2)用乘法结合律简算;
(3)按运算顺序计算,先算小括号内的,再算中括号内的,最后算括号外的;
(4)用乘法分配律简算;
(5)把原式变为
×
+
×
,然后用乘法分配律的逆运算简算.
(2)用乘法结合律简算;
(3)按运算顺序计算,先算小括号内的,再算中括号内的,最后算括号外的;
(4)用乘法分配律简算;
(5)把原式变为
3 |
18 |
8 |
19 |
3 |
18 |
11 |
19 |
解答:解:(1)327-59+33,
=327+33-59,
=360-(60-1),
=360-60+1,
=301;
(2)(8×0.8)×125,
=8×(0.8×125),
=8×100,
=800;
(3)15×[(48+24)÷18],
=15×[72÷18],
=15×4,
=60;
(4)24×(
-
),
=24×
-24×
,
=21-10,
=11;
(5)
×
+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
.
=327+33-59,
=360-(60-1),
=360-60+1,
=301;
(2)(8×0.8)×125,
=8×(0.8×125),
=8×100,
=800;
(3)15×[(48+24)÷18],
=15×[72÷18],
=15×4,
=60;
(4)24×(
7 |
8 |
5 |
12 |
=24×
7 |
8 |
5 |
12 |
=21-10,
=11;
(5)
3 |
18 |
8 |
19 |
11 |
18 |
3 |
19 |
=
3 |
18 |
8 |
19 |
3 |
18 |
11 |
19 |
=(
8 |
19 |
11 |
19 |
3 |
18 |
=1×
3 |
18 |
=
3 |
18 |
点评:做计算题时,注意审题,从数字特点出发,运用运算定律和性质,以及其它运算技巧,巧妙灵活地解答.
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